Climate change intensifies the drought vulnerability of river basins: a case of the Magat River Basin

Abstract

The socioeconomic impact of climate change on the drought vulnerability of a significant agricultural river basin in the Philippines, the Magat River Basin (MRB), was assessed using the AHP-entropy approach and GIS techniques. The different indicators of drought vulnerability dimen-sions have been evaluated and the results of this study imply that the current drought susceptibility of MRB is at 1.9–3.39 min–max scale or from low to above moderate, where the basin’s sensitivity and exposure account for 57 and 31% of the total vulnerability, respectively. And that the resulting adaptive capacity has a mitigating factor of only 12%, thereby construed to be very low. The Santa Fe and Subbasin 2 sub-watersheds are identified to be moderately susceptible to drought with an average rating of 3.1 and 3.25, respectively. Meanwhile, the average drought vulnerability rating of other subbasins is between 2.08 and 2.91, which is from a low to an approximately moderate level. The overall drought susceptibility of the basin is projected to increase due to climate change under future climate scenarios up to 30% (High) of the current level. Catalyzing effective policies and climate change governance are highly encouraged to further improve mitigation and adaptation measures.